Light-emitting device

ABSTRACT

A light-emitting device includes a base member, conductor wiring on an upper surface of the base member, a reflective member covering the upper surfaces of the base member and the conductor wiring and having apertures to expose part of the upper surface of the base member and part of the upper surface of the conductor wiring, a plurality of light sources bonded to the part of the upper surface of the conductor wiring located in the apertures with bonding members, and a reflector that is disposed on the reflective member and includes a plurality of first surrounding portions and a plurality of second surrounding portions surrounding the first surrounding portions, which respectively surround the light sources in a plan view. Each surrounding portion has inclined lateral surfaces that widen in an upward direction. An aperture in each second surrounding portion is smaller than an aperture in each first surrounding portion in the plan view.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of copending application Ser. No.16/457,412, filed on Jun. 28, 2019, which claims priority under 35U.S.C. § 119(a) to Application No. 2018-124179, filed in Japan on Jun.29, 2018, all of which are hereby expressly incorporated by referenceinto the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a light-emitting device.

2. Description of Related Art

Light-emitting devices each including a plurality of light sources havebeen proposed (see WO 2012/023459).

In a conventional light-emitting device, the luminance at an outerperipheral portion of the device may be lower than the luminance at thecentral portion of the device. This is because light emitted from otherportions of the device easily reaches the central portion of the devicebut does not easily reach the outer peripheral portion of the device.

SUMMARY OF THE INVENTION

The above problem can be solved by, for example, the following.

A light-emitting device includes a base member, conductor wiringdisposed on an upper surface of the base member, a reflective membercovering the upper surface of the base member and an upper surface ofthe conductor wiring and having a plurality of apertures in which partof the upper surface of the base member and part of the upper surface ofthe conductor wiring are located, a plurality of light sources bonded tothe part of the upper surface of the conductor wiring located in theplurality of apertures with bonding members, and a reflector that isdisposed on the reflective member and includes a plurality ofsurrounding portions, the plurality of surrounding portions respectivelysurrounding the plurality of light sources in a plan view, each of theplurality of surrounding portions having inclined lateral surfaces thatwiden in an upward direction, the plurality of surrounding portionsincluding a plurality of first surrounding portions and a plurality ofsecond surrounding portions surrounding the plurality of firstsurrounding portions, an area of an aperture in each of the plurality ofsecond surrounding portions being smaller than an area of an aperture ineach of the plurality of first surrounding portions in the plan view.

Effects of the Invention

In the light-emitting device as described above, the light density overthe surrounding portions at the outer peripheral portion of the deviceis higher than the light density over the surrounding portions at thecentral portion of the device. Accordingly, the luminance at the outerperipheral portion of the device can be similar to the luminance at thecentral portion of the device, so that the luminance over the device canbe more uniform throughout the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic plan view of a light-emitting device according toa first embodiment.

FIG. 1B is a diagram in which a plurality of first surrounding portionsin FIG. 1A are shaded in gray.

FIG. 1C is a diagram in which a plurality of second surrounding portionsin FIG. 1A are shaded in gray.

FIG. 1D is a schematic cross-sectional view taken along the line 1D-1Dof FIG. 1A.

FIG. 1E is a schematic, partial, enlarged view of FIG. 1D.

FIG. 1F is a schematic, partial, enlarged view of FIG. 1E.

FIG. 2A is a schematic cross-sectional view of another example of alight source in the first embodiment.

FIG. 2B is a schematic cross-sectional view of still another example ofa light source in the first embodiment.

FIG. 3 is a schematic cross-sectional view of another example of areflector in the first embodiment.

FIG. 4A is a diagram in which apertures of a reflective member in afirst surrounding portion and a second surrounding portion in aschematic, partial, enlarged view of FIG. 1A are shaded in gray.

FIG. 4B is a schematic cross-sectional view of still another example ofa reflector in the first embodiment.

FIG. 5A is a schematic plan view of a light-emitting device according toa second embodiment.

FIG. 5B is a diagram in which a plurality of first surrounding portionsin FIG. 5A are shaded in gray.

FIG. 5C is a diagram in which a plurality of second surrounding portionsin FIG. 5A are shaded in gray.

FIG. 5D is a diagram in which a plurality of third surrounding portionsin FIG. 5A are shaded in gray.

FIG. 5E is a schematic cross-sectional view taken along the line 5E-5Eof FIG. 5A.

FIG. 5F is a diagram in which apertures of a reflective member in afirst surrounding portion, a second surrounding portion, and a thirdsurrounding portion in a schematic, partial, enlarged view of FIG. 5Aare shaded in gray.

DETAILED DESCRIPTION OF EMBODIMENTS Light-Emitting Device 1 According toFirst Embodiment

FIG. 1A is a schematic plan view of a light-emitting device according toa first embodiment. FIG. 1B is a diagram in which a plurality of firstsurrounding portions 32 in FIG. 1A are shaded in gray to facilitate theunderstanding of the locations of the first surrounding portions 32.FIG. 1C is a diagram in which a plurality of second surrounding portions34 in FIG. 1A are shaded in gray to facilitate the understanding of thelocations of the second surrounding portions 34. In FIG. 1A, FIG. 1B,and FIG. 1C, only a base member 10, a reflective member 70,light-emitting elements 22, and a reflector 30 are illustrated, andillustrations of other members such as an optical member 40 are omitted,to facilitate the understanding of the shape of the reflector 30. FIG.1D is a schematic cross-sectional view taken along the line 1D-1D ofFIG. 1A. FIG. 1E is a schematic, partial, enlarged view of FIG. 1D. FIG.1F is a schematic, partial, enlarged view of FIG. 1E.

As shown in FIG. 1A to FIG. 1F, a light-emitting device 1 according tothe first embodiment includes the base member 10, conductor wiring 50disposed on an upper surface of the base member 10, the reflectivemember 70 covering the upper surface of the base member 10 and an uppersurface of the conductor wiring 50 and having a plurality of aperturesin which part of the upper surface of the base member 10 and part of theupper surface of the conductor wiring 50 are located, a plurality oflight sources 20 bonded to the part of the upper surface of theconductor wiring 50 located in the plurality of apertures with bondingmembers 60, and the reflector 30 that is disposed on the reflectivemember 70 and includes a plurality of surrounding portions. Theplurality of surrounding portions respectively surround the plurality oflight sources 20 in a plan view. Each of the plurality of surroundingportions has inclined lateral surfaces X widened upward. The pluralityof surrounding portions include the plurality of first surroundingportions 32 and the plurality of second surrounding portions 34surrounding the plurality of first surrounding portions 32. An area ofan aperture S8 in each of the plurality of second surrounding portions34 is smaller than an area of an aperture S7 in each of the plurality offirst surrounding portions 32 in the plan view. The details will bedescribed below.

(Light-Emitting Device 1)

The light-emitting device 1 is, for example, a direct-lit backlightdevice.

(Base Member 10)

The base member 10 is a member on or above which the light sources 20are mounted.

Examples of a material used for the base member 10 include ceramics andresins, such as phenolic resins, epoxy resins, polyimide resins, BTresins, polyphthalamide (PPA), and poly(ethylene terephthalate) (PET).Examples of the ceramics include alumina, mullite, forsterite, glassceramics, and nitride (such as AlN) and carbide (such as SiC) ceramics,and LTCC. In the case where a resin is used as a material of the basemember 10, glass fiber or an inorganic filler, such as SiO₂, TiO₂, orAl₂O₃, can be mixed into the resin to improve the mechanical strength,reduce the thermal expansion coefficient, and improve the lightreflectance. A metal substrate in which an insulating layer is disposedon a surface of a metal member may be used as the base member 10.

A thickness of the base member 10 can be selected appropriately. Thebase member 10 may be, for example, a flexible substrate that can bemanufactured using a roll-to-roll manner, or may be a rigid substrate.The rigid substrate may be a slim rigid substrate that is bendable.

(Conductor Wiring 50)

The conductor wiring 50 for supplying electricity to the light sources20 (i.e., light-emitting elements 22) can be disposed at least on anupper surface of the base member 10. The conductor wiring 50 iselectrically connected to electrodes of the light sources 20 (i.e.,light-emitting elements 22) and is configured to supply a current (i.e.,electricity) from outside.

A material of the conductor wiring 50 can be appropriately selected inaccordance with a material used for the base member 10 and a method ofmanufacturing the base member 10. For example, in the case where aceramic is used as a material of the base member 10, a material of theconductor wiring 50 is preferably a material having a melting point thatis high enough to endure sintering temperatures of a ceramic sheet. Ametal with a high melting point, such as tungsten or molybdenum, ispreferable for a material of the conductor wiring 50. In addition, amember in which a surface of a metal member made of such a metal iscovered with another metal material, such as nickel, gold, or silver, byplating, sputtering, vapor deposition, or the like can be used as theconductor wiring 50. In the case where a glass epoxy resin is used as amaterial of the base member 10, a material that is easy to process ispreferably used as a material of the conductor wiring 50.

The conductor wiring 50 can be formed on one or both of oppositesurfaces of the base member 10 by a method such as vapor deposition,sputtering, or plating. Metal foil attached to the base member 10 bypressing may serve as the conductor wiring 50. The conductor wiring 50can be patterned to have a predetermined shape by forming a mask on theconductor wiring 50 by printing or photolithography and then performingetching.

(Reflective Member 70)

The reflective member 70 is an insulating member that reflects light orreduces leakage and absorption of light to increase light extractionefficiency of the light-emitting device 1. The reflective member 70covers the upper surface of the base member 10 and the upper surface ofthe conductor wiring 50. For example, a member containing a white fillercan be used as the reflective member 70. For the reflective member 70,any appropriate insulating material can be used, and a material that isunlikely to absorb light emitted from the light-emitting elements 22 isparticularly preferable. Specific examples of the material used for thereflective member 70 include an epoxy resin, a silicone resin, amodified silicone resin, a urethane resin, an oxetane resin, an acrylicresin, a polycarbonate resin, and a polyimide resin.

The reflective member 70 has a plurality of apertures S7 and S8 in whichpart of the upper surface of the base member 10 and part of the uppersurface of the conductor wiring 50 are located. For example, as shown inFIG. 4A and FIG. 4B, the area of the aperture S8 in each of the secondsurrounding portions 34 is smaller than the area of the aperture S7 ineach of the first surrounding portions 32 in a plan view. With thisstructure, the reflective member 70 reflects more light in the secondsurrounding portions 34 than in the first surrounding portions 32, sothat the light density over the surrounding portions at the outerperipheral portion of the light-emitting device is higher than the lightdensity over the surrounding portions at the central portion of thedevice. Accordingly, a luminance at the outer peripheral portion of thedevice can be similar to a luminance at the central portion of thedevice, so that the luminance over the device can be more uniformthroughout the device.

(Light Sources 20)

The plurality of light sources 20 are bonded to the part of the uppersurface of the conductor wiring 50 located in the plurality of aperturesS7 and S8 with the bonding members 60.

The intervals between the light sources 20, in other words, intervals Pbetween adjacent light sources 20, are preferably uniform (including thecase where the intervals P are varied to the extent that is small enoughto be regarded as uniform) in the longitudinal and lateral directions ina plan view. In the present embodiment, the area of the aperture S8 ineach of the second surrounding portions 34 is smaller than the aperturearea S7 of each of the first surrounding portions 32. A luminancesimilar to the luminance at the central portion of the light-emittingdevice can be obtained at the outer peripheral portion of the devicewithout comparatively complicated design changes such as changes in thearrangement of the light sources 20. Thus, designing of thelight-emitting device 1 is facilitated. In addition to employingdifferent sizes of the aperture areas S7 and S8 of the reflective member70, by employing the first surrounding portions 32 that differ in sizefrom the second surrounding portions 34 of the reflector 30, such as byallowing an upper aperture area S2 defined by the upper ends of theinclined lateral surfaces X of each of the second surrounding portions34 to be smaller than an upper aperture area S1 defined by the upperends of the inclined lateral surfaces X of each of the first surroundingportions 32, a luminance similar to the luminance at the central portionof the device is more easily obtained at the outer peripheral portion ofthe device. Thus, the need for changes in the arrangement of the lightsources 20 is further reduced, and design flexibility of thelight-emitting device 1 can be more easily ensured.

Each light source 20 may include the light-emitting element 22 such as alight-emitting diode. The light-emitting element 22 includes, forexample, a light-transmissive substrate and a semiconductor layerlayered on the substrate. For example, sapphire can be used for thelight-transmissive substrate. The semiconductor layer includes, forexample, an n-type semiconductor layer, an active layer, and a p-typesemiconductor layer in this order from the substrate. For example, ZnSe,a nitride semiconductor (InxAl_(y)Ga_(1-x-y)N, where 0≤X, 0≤Y, andX+Y≤1), GaP, GaAlAs, or AlInGaP can be used for the semiconductor layer.For example, an n-side electrode is formed on the n-type semiconductorlayer, and a p-side electrode is formed on the p-type semiconductorlayer.

Each light source 20 may include a sealing member 26. The sealing member26 protects the light-emitting element 22 against external environmentsand optically controls light that exits from the light-emitting element22. The sealing member 26 is disposed on or above the base member 10 tocover the light-emitting element 22. An end portion of each of theapertures S7 and S8 of the reflective member 70, the end portion facingthe light source, may be located inside or outside the sealing member 26in a plan view. In the case where the end portion facing the lightsource is located inside the sealing member 26, each of the apertures S7and S8 is covered with the sealing member 26. In the case where the endportion facing the light source is located outside the sealing member26, the sealing member 26 is disposed inside each of the apertures S7and S8.

Examples of the material used for the sealing member 26 include an epoxyresin, a silicone resin, a mixture of these resins, and alight-transmissive material such as glass. Among these materials, asilicone resin is preferably selected in consideration of lightresistance and ease of molding. The sealing member 26 can contain alight-diffusing agent, a wavelength conversion member, such as aphosphor, that absorbs light emitted from the light-emitting element 22to emit light with a wavelength different from the wavelength of thelight emitted from the light-emitting element 22, and a coloring agentcorresponding to the emission color of the light-emitting element 22.

The sealing member 26 can be formed by, for example, molding such ascompression molding or injection molding, dropping, or drawing.Alternatively, by optimizing the viscosity of a material of the sealingmember 26, the shape of the sealing member 26 can be controlled due tosurface tension of the material of the sealing member 26. In the case ofdropping or drawing, the sealing member 26 can be formed in a simplermanner without using molds. Adjustment of the viscosity may be achievedby employing a material having a desired viscosity as a material of thesealing member 26, or by using the above-described light-diffusingagent, wavelength conversion member, or coloring agent.

Each light source 20 preferably has a batwing light distributioncharacteristic. In such a light distribution characteristic, the amountof light emitted directly upward from each light source 20 can bereduced, and a broad light distribution of the light source 20 can beachieved. Accordingly, the thickness of the light-emitting device 1 canbe reduced, particularly in the case where the light-transmissiveoptical member 40 is disposed to face the base member 10. Thus, alight-emitting device with a small thickness can be provided whileallowing the luminance at the outer peripheral portion of the device tobe the same as the luminance at the central portion of the device.

The expression “batwing light distribution characteristic” refers tosuch a light distribution characteristic that the luminance at thecentral portion is lower than the luminance at the outer peripheralportion. Examples of the batwing light distribution characteristicinclude, with an optical axis L being 0 degrees, a light distributioncharacteristic having an emission intensity distribution in which theemission intensity at angles with absolute values larger than 0 degreesis high and a light distribution characteristic having an emissionintensity distribution in which the emission intensity is the highest ina range of approximately 45 degrees to 90 degrees.

Each light source 20 may include a reflective layer 28 on the uppersurface of the light-emitting element 22. In this case, the sealingmember 26 can cover, for example, the light-emitting element 22 and thereflective layer 28. With the sealing member 26 disposed in this manner,forming the sealing member 26 into a shape such as a shape describedbelow shown in FIG. 2A easily provides the batwing light distributioncharacteristic.

FIG. 2A is a schematic cross-sectional view of another example of alight source in the first embodiment. A sealing member 26 may have, forexample, a domical shape or, as shown in FIG. 2A, a shape that broadensthe distribution of light emitted from the light-emitting element 22,more specifically, a shape having a depressed portion directly above thelight-emitting element. With this structure, the sealing member 26functions as a lens to broaden the light distribution, and the batwinglight distribution characteristic can be obtained without the reflectivelayer 28 as described above. Alternatively, the combination of thereflective layer 28 and the sealing member 26 that functions as a lenscan more easily provide the batwing light distribution characteristic.

FIG. 2B is a schematic cross-sectional view of still another example ofa light source in the first embodiment. Each light source 20 may includea reflective layer 28 over a sealing member 26 as shown in FIG. 2B. Withthis structure, the reflective layer 28 reflects light emitted upwardfrom the light-emitting element 22, so that the amount of light emitteddirectly upward from the light-emitting element 22 is reduced.Accordingly, the batwing light distribution characteristic can be easilyachieved.

The reflective layer 28 may be a metal film or a dielectric multilayerfilm.

It is preferable that the light sources 20 can be driven separately fromone another. It is particularly preferable that light control (such aslocal dimming and high dynamic range: HDR) can be performed with respectto each of the light sources 20.

(Reflector 30)

The reflector 30 reflects light emitted from the light sources 20. Thereflector 30 preferably has an average reflectance of 70% or more oflight emitted from the light sources 20 in a wavelength range of 440 nmto 630 nm. For example, a resin member containing a reflective materialmade of particles of a metal oxide such as titanium oxide, aluminumoxide, or silicon oxide, or a member in which a reflective member isdisposed on a surface of a resin member containing no reflectivematerial can be used for the reflector 30.

The reflector 30 is disposed on the reflective member 70 and includes aplurality of surrounding portions, which respectively surround theplurality of light sources 20 in a plan view. A single surroundingportion surrounds a single light source. The plurality of surroundingportions include the first surrounding portions 32 and the secondsurrounding portions 34 surrounding the first surrounding portions 32.Each of the plurality of surrounding portions has the inclined lateralsurfaces X widened upward. The upper aperture area S2 defined by theupper ends of the inclined lateral surfaces X of each of the secondsurrounding portions 34 is preferably smaller than the upper aperturearea S1 defined by the upper ends of the inclined lateral surfaces X ofeach of the first surrounding portions 32. This structure allows thelight density over the second surrounding portions 34 to be even higherthan the light density over the first surrounding portions 32; in otherwords, this structure allows the light density at the outer peripheralportion of the light-emitting device to be higher than the light densityover the central portion of the device. A luminance similar to theluminance at the central portion of the device is thus more easilyobtained at the outer peripheral portion of the device. The “lightdensity” refers to the degree of intensity of light per unit area.

The reflector 30 has a thickness T in a range of, for example, 100 μm to300 μm.

The plurality of surrounding portions of the reflector 30 eachpreferably have a planar portion extending from the lower ends of theinclined lateral surfaces X toward the light source 20. In FIG. 1E, theinclination angle of each of the inclined lateral surfaces X of thesecond surrounding portions 34 is larger than the inclination angle ofeach of the inclined lateral surfaces X of the first surroundingportions 32.

A distance D2 between an end portion of the planar portion of the secondsurrounding portions 34, the end portion facing a corresponding one ofthe light sources, and an end portion of the corresponding light sourceis preferably smaller than a distance D1 between an end portion of theplanar portion of the first surrounding portions 32, the end portionfacing a corresponding one of the light sources, and an end portion ofthe corresponding light source as shown in, for example, FIG. 4B. Thisstructure allows the light density over the second surrounding portions34 to be even higher than the light density over the first surroundingportions 32, so that the light density over the surrounding portions atthe outer peripheral portion of the light-emitting device is higher thanthe light density over the surrounding portions at the central portionof the device. Thus, a luminance similar to the luminance at the centralportion of the device is more easily obtained at the outer peripheralportion of the device.

FIG. 3 is a schematic cross-sectional view of another example of areflector in the first embodiment. A height H2 between the upper surfaceof the base member 10 and the upper end of each of the inclined lateralsurfaces X of the second surrounding portions 34 is preferably greaterthan a height H1 between the upper surface of the base member 10 and theupper end of each of the inclined lateral surfaces X of the firstsurrounding portions 32 as shown in FIG. 3. This structure increases theamount of light that is multiple-reflected within the second surroundingportions 34, which further increases the light density over the secondsurrounding portions 34, so that the luminance at the outer peripheralportion of the light-emitting device can be increased.

(Optical Member 40)

The optical member 40 faces the base member 10 across a plurality oflight sources 20. A distance K2 between the upper end of each of theinclined lateral surfaces X and the optical member 40 is preferablyequal to or less than a half of a distance K1 between the upper surfaceof the base member 10 and the upper end of each of the inclined lateralsurfaces X. This structure allows a depth of each of the firstsurrounding portions 32 and the second surrounding portions 34 to berelatively great in proportion to the distance between the reflector 30and the optical member 40, so that the number of repetitions of multiplereflection of light within the first surrounding portions 32 and thesecond surrounding portions 34 can be increased. Accordingly, thedensity of light from each surrounding portion at the location of theoptical member 40 can be enhanced.

For example, a light-transmissive member such as a semitransparentmirror can be used for the optical member 40. For the semitransparentmirror, for example, a material that reflects a part of incident lightand transmits another part of the light can be used.

The semitransparent mirror preferably has a reflectance with respect tolight incident in an oblique direction lower than a reflectance thereofwith respect to light incident in a perpendicular direction. That is,the semitransparent mirror preferably has a property in which areflectance of the semitransparent mirror with respect to light emittedfrom each light source 20 parallel to the optical axis direction is highand a light reflectance decreases in accordance with increase in theradiation angle (in other words, the property in which the amount oflight transmitted through the semitransparent mirror increases). Lightparallel to the optical axis direction is regarded to have a radiationangle of 0 degrees. This structure can easily provide a uniformluminance distribution when the semitransparent mirror is observed fromthe emission surface.

For example, a dielectric multilayer film can be used for thesemitransparent mirror. By using a dielectric multilayer film, areflective film with low light absorption can be obtained. Further, thereflectance can be adjusted as desired by changing the design of thefilm, and the reflectance with respect to an angle of emitted light canbe controlled. For example, with the dielectric multilayer film designedto have a reflectance with respect to light incident in an obliquedirection on the semitransparent mirror lower than a reflectance thereofwith respect to light incident perpendicularly on the semitransparentmirror, a property can be easily realized in which a reflectance withrespect to light incident perpendicularly on the light-extractingsurface is higher and a reflectance decreases in accordance withincrease in the angle of incident light with respect to thelight-extracting surface.

The light-emitting device 1 may include a light diffusing plate at theemission surface of the optical member 40. The light diffusing platediffuses light emitted from a plurality of light sources 20 to reduceunevenness in luminance. For the light diffusing plate, a material thatis unlikely to absorb visible light, such as a polycarbonate resin, apolystyrene resin, an acrylic resin, or a polyethylene resin can beused. For example, a member that contains a base material and a materialhaving a refractive index different from the refractive index of thebase material, or a member made of a base material and having a surfacethat is processed so as to scatter light can be used for the lightdiffusing plate.

(Bonding Members 60)

The light-emitting device 1 includes the bonding members 60. The bondingmembers 60 fix the light sources 20 to the base member 10 and/or theconductor wiring 50. Examples of the bonding members 60 includeinsulating resins and electrically-conductive members. In the case wherethe light sources 20 are flip-chip mounted, electrically-conductivemembers can be used for the bonding members 60. Examples of the bondingmembers 60 include Au-containing alloys, Ag-containing alloys,Pd-containing alloys, In-containing alloys, Pb—Pd-containing alloys,Au—Ga-containing alloys, Au—Sn-containing alloys, Sn-containing alloys,Sn—Cu-containing alloys, Sn—Cu—Ag-containing alloys, Au—Ge-containingalloys, Au—Si-containing alloys, Al-containing alloys, Cu—In-containingalloys, and mixtures of metals and fluxes.

For example, a member in a form of liquid, paste, or solid(sheet-shaped, block-shaped, powdered, or wire-shaped) may be usedsingly or in combination for the bonding members 60. Appropriatematerials can be selected in accordance with the shape of the basemember 10 and the composition. In the case where electrically connectingthe light sources 20 to the conductor wiring 50 and mounting or fixingthe light sources 20 above or to the base member 10 are not performed atonce but are performed separately, wires other than the bonding members60 may be used to electrically connect the light sources to theconductor wiring 50.

As described above, in the light-emitting device 1 according to thefirst embodiment, the area of the aperture S8 in each of the secondsurrounding portions 34 is smaller than the area of the aperture S7 ineach of the first surrounding portions 32 in a plan view. Thus, thereflective member 70 reflects more light in the second surroundingportions 34 than in the first surrounding portions 32, so that the lightdensity over the surrounding portions at the outer peripheral portion ofthe device is higher than the light density over the surroundingportions at the central portion of the device. Accordingly, a luminanceat the outer peripheral portion of the device can be similar to aluminance at the central portion of the device, so that the luminanceover the device can be more uniform throughout the device.

Light-Emitting Device 2 According to Second Embodiment

FIG. 5A is a schematic plan view of a light-emitting device according toa second embodiment. FIG. 5B is a diagram in which the plurality offirst surrounding portions 32 in FIG. 5A are shaded in gray tofacilitate the understanding of the locations of the first surroundingportions 32. FIG. 5C is a diagram in which the plurality of secondsurrounding portions 34 in FIG. 5A are shaded in gray to facilitate theunderstanding of the locations of the second surrounding portions 34.FIG. 5D is a diagram in which a plurality of third surrounding portions36 in FIG. 5A are shaded in gray to facilitate the understanding of thelocations of the third surrounding portions 36. FIG. 5E is a schematiccross-sectional view taken along the line 5E-5E of FIG. 5A. FIG. 5F is adiagram in which apertures of a reflective member in a first surroundingportion, a second surrounding portion, and a third surrounding portionin a schematic, partial, enlarged view of FIG. 5A are shaded in gray.

As shown in FIG. 5A to FIG. 5F, a light-emitting device 2 according tothe second embodiment differs from the light-emitting device 1 accordingto the first embodiment in that the plurality of surrounding portionsinclude the third surrounding portions 36 between the first surroundingportions 32 and the second surrounding portions 34, and in that the areaof an aperture S9 in each of the third surrounding portions 36 issmaller than the area of the aperture S7 in each of the firstsurrounding portions 32 and larger than the area of the aperture S8 ineach of the second surrounding portions 34 in a plan view. In thelight-emitting device 2 according to the second embodiment, the relationthe light density over the second surrounding portions 34>the lightdensity over the third surrounding portions 36>the light density overthe first surrounding portions 32 is satisfied, and the light densityover the device gradually increases from the central portion toward theouter peripheral portion of the device. Accordingly, the luminance atthe outer peripheral portion of the device can be similar to theluminance at the central portion of the device, so that the luminanceover the device can be more uniform throughout the device. It ispreferable that an upper aperture area S3 defined by the upper ends ofthe inclined lateral surfaces X of each of the third surroundingportions 36 be smaller than the upper aperture area S1 in each of thefirst surrounding portions 32 and larger than the upper aperture area S2in each of the second surrounding portions 34. This structure furtherfacilitates establishment of the relation between the light densitiesdescribed above. Thus, a luminance similar to the luminance at thecentral portion of the device can be obtained at the outer peripheralportion of the device, so that the luminance over the device can be evenmore uniform throughout the device.

Certain embodiments of the present invention have been described above,but descriptions thereof do not limit the scope of in the claims.

1. A light-emitting device comprising: a base member; conductor wiring disposed on an upper surface of the base member; a reflective member covering the upper surface of the base member and an upper surface of the conductor wiring and having a plurality of apertures in which part of the upper surface of the base member and part of the upper surface of the conductor wiring are located; a plurality of light sources bonded to the part of the upper surface of the conductor wiring located in the plurality of apertures, respectively; a light diffusing plate diffusing light emitted from the plurality of light sources; and wherein the plurality of apertures comprises a plurality of first apertures and a plurality of second apertures surrounding the plurality of first apertures, and wherein an area of the respective second aperture is smaller than an area of the respective first aperture in the plan view.
 2. The light-emitting device according to claim 1, wherein the respective aperture has a circle-like shape in a plan view.
 3. The light-emitting device according to claim 1, comprising a reflector having a plurality of lateral surfaces, wherein the plurality of lateral surfaces are disposed such that the plurality of light sources are respectively surrounded by the plurality of lateral surfaces.
 4. The light-emitting device according to claim 3, wherein the respective second aperture is located close to the outside of the base member in an upper aperture area defined by upper ends of the lateral surfaces in a plan view.
 5. A light-emitting device comprising: a base member; conductor wiring disposed on an upper surface of the base member; a reflective member covering the upper surface of the base member and an upper surface of the conductor wiring and having a plurality of apertures in which part of the upper surface of the base member and part of the upper surface of the conductor wiring are located; a plurality of light sources bonded to the part of the upper surface of the conductor wiring located in the plurality of apertures, respectively; an optical member facing the base member across the plurality of light sources; and wherein the plurality of apertures comprises a plurality of first apertures and a plurality of second apertures surrounding the plurality of first apertures, and wherein an area of the respective second aperture is smaller than an area of the respective first aperture in the plan view.
 6. The light-emitting device according to claim 5 wherein the respective aperture has a circle-like shape in a plan view.
 7. The light-emitting device according to claim 5, comprising a reflector having a plurality of lateral surfaces, wherein the plurality of lateral surfaces are disposed such that the plurality of light sources are respectively surrounded by the plurality of lateral surfaces.
 8. The light-emitting device according to claim 7, wherein the respective second aperture is located close to the outside of the base member in an upper aperture area defined by upper ends of the lateral surfaces in a plan view.
 9. The light-emitting device according to claim 5, comprising a a light diffusing plate disposed at the emission surface of the optical member. 